The Orchid Family

All orchids belong to the Orchidaceae which is one of the largest families of flowering plants on the planet. Orchids are found in all habitats except deserts and ice sheets.

The highest density of orchids grow in the rainforests all over the world, loving the humidity and shaded provided by these environments. Not all orchids like hot conditions, though. Many need cooler climates, as where they grow is at high altitudes in the mountains where the temperatures can drop very low at night.  As forest dwelling plants, many orchids grow as ‘epiphytes’, clinging to the bark of trees and have specialised roots that can draw water from the air. Others have swollen stems called pseudobulbs that store food and water in times of drought. Adaptations like these have enabled orchids to occupy niches from the forest floor to the tops of the trees. There are also many orchids that grow in the ground and are known as 'terrestrials'. 

In New Zealand there are over 100 native orchid species, most are terrestrial and have small flowers.

Five Sub-Families

Apostasioideae	Cypripedioideae	Vanilloideae
Epidendroideae	Orchidoideae

Orchids in each of the five main sub-families are characterised by common structural elements.  Each subfamily is divided into many genera, and each genus into many species, again on the basis of shared characteristics. Some 80% of the orchids are in the subfamily Epidendroideae and most of the well known cultivated genera belong to this group of mainly tropical epiphytes. Each orchid has its own Latin name which includes the genus and species e.g. Cattleya labiata.

Names often change as scientists debate which flower fits where among the more than 22,500 species and 800 genera. Around 200-300 new species added every year and more than 100,000 orchid hybrids (cultivars) have been created by horticulturists. See Royal Botanic Gardens, Kew for further detail about the origins and affinities of orchids.

Two Orchid Growth Types

Monopodial Monopodial (single stem) orchids have stems that grow indefinitely. In this type of orchid the leaves always grow from the end of the stem. The flowers grow from the side of the stem (not from the end). Popular cultivated monopodial orchids include Vanda, Vanilla and Phalaenopsis orchids.

Sympodial The Sympodial (multiple stem) orchids are characterised by having a succession of shoots or bulb-like stems (pseudobulbs), each arising from the base of the one before it. The flower spikes arise from the pseudobulb or from the rhizome. The majority of the tropical orchids branch this way and include the well known cultivated genera: Cattleya, Dendrobium, Epidendrum, Laelia, Oncidium Paphiopedilum and Spathoglottis.

Top of Page   Print This Page